FILTER CAKE - A FIELD AND GLASSHOUSE EVALUATION

The results are reported of field experiments with filter cake in a number of different soil groups, with particular reference to soil P levels and the treatment effects on cane quality. It is concluded that the greatest industrial advantage can be gained by using filter cake on midland mistbelt soils such as the Inanda series. The factor influencing cane quality is associated with nitrogen availability which, amongst other factors, was measured in a glasshouse pot experiment. Nitrogen availability is apparently a function of both the C/N ratio of filter cake and the soil type to which it is applied. Other characteristics of filter cake such as its nematicidal properties and its moisture content are discussed and its value as an aid in winter planting is con' sidered.